It is well known that it is desirable to customize the chemical doses delivered to commercial laundry machines in accordance with the type of wash load (e.g., shirts, towels, etc.) being laundered. When a microprocessor controlled chemical dispenser is used, the type of wash load can be communicated to the chemical dispenser by sending it signals representing a corresponding wash classification code.
Programmable washing machines generally have the ability to generate trigger signals, which are used to communicate feed requests to the chemical dispenser. When the chemical dispenser also receives a wash classification code for each load of laundry to be washed, the trigger signals can be interpreted differently for each different wash classification code, enabling the chemical dispenser to customize the chemical doses delivered to commercial laundry machines in accordance with the type of wash load.
Some programmable washing machines have only a few "triggers," which are signals used to communicate with the liquid chemical dispenser, and some can activate only one or two trigger signals at a time. These trigger generation limitations have made it impractical to use to trigger signals to communicate wash classification codes to chemical dispensers, because the number of distinct wash classifications required for many commercial and industrial washing machine systems exceeds the number of available distinct trigger signals.
To achieve chemical dosing and data logging based on wash classification, despite the trigger signal limitation in many programmable washing machines, some chemical dispenser manufacturers produce "Classification ID modules". These are attached at the washer, and the person operating the washer dials in the appropriate wash classification number at the start of a new load of wash. The dispenser receives signals corresponding to the number dialed in and performs custom chemical dosing and data logging in accordance with the wash classification dialed in by the washing machine operators.
The Classification ID modules add to the cost of buying and operating a commercial washing machine. Also, Classification ID modules create additional opportunities for operator error. If the operator does not enter the correct wash classification every time a new load gets washed, incorrect chemicals or quantities may be dispensed to the washing machine for those wash loads where the operator enters an incorrect wash classification.
The present invention produces the same results as the classification ID modules, but avoids the cost of buying and installing a "Classification ID module", and the possible operator errors in its use. More specifically, the present invention provides a method of overcoming the trigger signal limitation in programmable washing machines so as to allow a programmable washing machine to communicate to a chemical dispenser a sufficient range of wash classification values to cover all the wash classifications used in typical commercial laundries.
Another goal of the present invention is to enable a chemical dispenser to reliably sense the start and end of a washing machine cycle (i.e., the start and end of washing a load) for data logging purposes. Most or many washing machines do not have externally accessible Cycle Start and Cycle End signals that are suitable for sensing by a chemical dispenser or other computer controlled device. The present invention provides a method of using trigger signals in programmable washing machines for providing reliable Cycle Start and Cycle End signals to a chemical dispenser.
Yet another goal of the present invention is to provide a system with safeguards to avoid the dispensing of the wrong chemicals to a washing machine for a particular type of washing machine load. While it may be impossible to avoid the dispensing of wrong chemicals if the washing machine is improperly programmed, or if one of the trigger signals is defective, the present invention provides safeguards for avoiding wrong chemical dispensing due to power outages at the chemical dispenser and due to a washer operator starting a new cycle before a prior wash cycle has run to completion.